Heat Shock Practice

It’s always good to practice your methods of torture.

On May 12, I figured out my methods for the heat shock experiment I wnat to conduct with the C. gigas we brought back from Manchester. The reason why I want to conduct a heat shock is because I want to see if different stressors methylate different regions of the genome, and if a combination of stressors will create a unique methylation pattern.

The first thing I did was create a hot water bath with saltwater from our flow-through system. Although the water bath has a temperature reading on it, I also added a thermometer to double check. The temperature I aimed for was 40 ºC.


After checking that the temperature was at 40ºC, I grabbed four oysters from our set-up…


…and plopped them in the water bath!


I started the heat shock treatment at 4:17 p.m., and let it run for an hour. At 5:17 p.m., I killed the heat and took the oysters out. The temperature on the water bath and on the thermometer read around 40ºC.

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I checked mortality everyday since then, and they’re still alive! Looks like one hour at 40ºC should work for a heat shock.

Things I need to do before Monday:

  • Find a heater for the 100 L tanks
  • Figure out how many oysters to shock
  • Find a time to start heating the water before the day of the shock

The bigger question, however, is whether or not I’m going to do a heat shock at all! Because I have 45 oysters for each OA condition, and not all of those oysters will be fertile when I’m ready to spawn and the sex ratio of oysters can’t be predicted, I don’t want to use oysters I could have spawned with. I may apply a heat shock to some of the oysters that were kept on the ambient line continously, and then cross those with oysters from the OA treatment. Either way, I’m going to expose spat to both OA and heat shock conditions, so I’m still going to assess the effect of multiple stressors on the next generation.

Written on May 17, 2017